Annealing steel sheets



Dec. 29, 1925' J. T. HAY

ANNEALI NG STEEL SHEETS Filed Jan. 19, 1925 2 Sheets-Sheet 1 gnvcnfoz John TH attouieqil Dec. 29, 1925 1,567,143

J. T. HAY 4 ANNEALING STEEL SHEETS Filed Jan. 19. 1925 2 Sheets-Sheet 2 FIG.5

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affozncif l .aenee Dec. 29, 1925.

- chrome steel .or iron ,UNITED STATES 1,567,143 PATENT OFFICE.

JOHN THOMAS HAY, CFO-ANTON, OHIO, ASSIGNOR TO UNITED ALLOY STEEL COB- IPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

AIN'IIEAILIIYI'' STEEL SHEETS.

Application filed January 19, 1925. Serial No. 3,809.

To all whom it may conccm:

Be it known that I, JOHN Tnoms HAY, a citizen of the United States, residing at Canton, in the county. of Stark and State of Ohio, have invented certain new and useful Improvements in Annealing Steel Sheets,

The invention relates to the annealing of sheets, comprising a chrome alloy of steel or iron which may contain silicon or other alloy elements.

When such sheets are annealed by ordinary methods, there is formed an insoluble scale in the sheet surfaces, which cannot "be removed by any known pickling process. Moreover, such sheets are not easily adapted to deep drawing processes.

The objects of the present invention are i to provide a method of annealing chrome steel sheets, wherein the scale formed on the sheet surfaces may be removed by pickling; and to produce by the above method a sheet which when finished has a fine grained structure adapted to deep drawing. Y

These -object-s'may be attained by separatel placing the sheets onedge in a heating urnace, afterthey have been first heated and reduced by rolling, and admitting a quantity of oxygen into the furnace for rendering soluble in a pickling solution the scale formed upon' the sheets by the prior rolling and annealing processes or by the instant annealing process, and rapidly and uniformly heating the sheets in the furnace to produce a fine granular structure adapted for deep drawing.

One form of apparatus for carrying out the invention is illustrated in the accompanying drawing, forming part hereof, in which-- Figure 1 is aplan cross section of a heat- 1 ing furnace for carrying out the invention,

- as on line 1-1, Fig. 2;

Fig. 2, a longitudinal cross-section: of the same, as on line 3-3, Fig. 2, showing a pile of sheets partially arranged on edge in the furnace; and V Fig. 4, a transverse cross-section of the same as on line 44, Fig. 2, showing the sheets arranged on edge in the furnace, as during the annealing process.

Similar numerals refer to similar .parts throughout the several figures of the draw- The furnace may be an ordinary sheet heating furnace, including side walls 1 and 2, end walls 3 and 4, and arched top 5, built in any well known manner upon a foundatron indicated at 6, and

providing an intenor which is divided by baflle wall 7 to form a, firing chamber indicated by 8 and a sheet chamber indicated by 9; such a furnace being sometimes known as a semi-mufile furnace.

Within the firing chamber 8, a grate 10 is secured, and the end wall 3 is provided with a fire door 11 above the grate, and a draft door 12 below the grate for firing the grate with a fuel indicatedat 13, and controlling the combustion of the same. It is to be understood that any other desired form of heating means may be employed in place of the means .illustrated.

End wall 4 is provided with a sheet door 14, having an opening and closing mechanism indicated at 15, permitting access to the sheet chamber 9.

A fioor 16 preferably having a series of longitudinal notches 16" is provided in the sheet chamber and supported by a series of spaced longitudinal flue walls 17 to provide a plurality of fines 18 beneath the floor 16, and in communication with the sheet chamber, through apertures 18 in the floor.

Flues 18 are directed into a transverse tunnel 19 situated between the end wall 4 and the bafile wall 7, and tunnel 19 communicates by way of side stacks 20 and 21 with the centrally located main stack 22, as shown. A check damper indicated at 23 is provided in the main stack 22 for controlling the gas flow through the stack.

The same furnace may be used to heat the chrome steel sheets 24 before rolling, but as here shown in Fig. 3, a pile of sheets 25 has been first heated, then rolled, and then inserted, preferably singly, through the door rolls have a tightly adhering scale after ordinary annealing in a reducing atmosphere, which scale is insoluble in ordinary pickling 'baths. This scale is increased and rendered more. insoluble by the annealing process.

By the present method the sheets are preferably heated in the furnace for a period of about twenty minutes, depending upon their thickness, and thenthe check draft 23 is adjusted to permit a predeterminedfiow I ofair through the furnace and around the separated sheets as indicated bythe arrows.

This flow of ai 1 for a period of about ten minutes, and thelconstituent oxygen causes the formation upon the sheet, surfaces of. a

scale which is readily soluble in a pickling bath containing sulphuric acid and hydrochloric acid, which acids may be in proportions of of sulphuric'and 2% ofhydrochlorie, as set forth in my Letters Patent No.

The sheets are thus subject to a hot annealing atmosphere which is first reducing and then oxidizing for a total period of about thirty minutes, at the end of which form a soluble scale thereon.

2. The method of annealing chrome steel sheets which includes heat-ing separated sheetsfor annealing in an oxidizing atmosphere to form a soluble scale thereon.

3. The method of annealing chrome, steel sheets which includes heating the "sheets for vannealing in an'oxidizing atmosphere, and intermittently agitating the sheets during the heating period, to form a soluble scale 7 thereon.

4:. The method of annealing chrome steel sheets "which includes heating the sheets for annealing in a reducing atmosphere and phere to form a soluble scale thereon.

5; Themethod of annealing chrome steel sheets which includes heating the sheets for about ten minutes in an oxidizing atmos phere. I Y

6. The method of annealing chrome steel sheets which includes heating the sheets in a reducing atmosphere and then heatingthe 7. The method of annealing chrome steel sheets which includes heating the sheets in a reducing atmosphere for about twenty minutes and then heating the sheets in an oxidizing atmosphere.

then heating them in an oxidizing atmossheets for about ten minutes in an'oxidizing I atmosphere.

8. The method of annealing chrome steel sheets which includes heating the sheets in areducing atmosphere for about twenty minutes and then heating the sheets in an oxidizing atmosphere for about ten minutes.

9. The" methodiof treating chrome steel sheets which includes annealing the sheets by heating them in an oxidizing atmosphere to form a soluble scale thereon, and then pickling the sheets in sulphuric and hydro-- chloric acids.

10. The method of treating chrome steel sheets which includes annealing the sheets by heating them in an atmosphere which is first reducing and then oxidizing to form a soluble solution thereon, and then pickling the sheets.

In testimony that Iclaim the above, have hereunto subscribed myv name. JOHN THOMAS HAY., 

